


Siblinglove

by SympatriCuckoo



Category: Undertale (Video Game)
Genre: Bestiality, Come Inflation, Come Swallowing, Consensual Sex, Deepthroating, Dirty Talk, Ecto-Genitalia, Knotting, M/M, Multi, Oral Knotting, Other, Pet Play
Language: English
Status: Completed
Published: 2016-04-04
Updated: 2016-04-04
Packaged: 2018-05-31 06:42:33
Rating: Explicit
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 1
Words: 1,526
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/6459898
Author URL: https://archiveofourown.org/users/SympatriCuckoo/pseuds/SympatriCuckoo
Summary: <blockquote class="userstuff">
              <p>
  <em> With a jolt, Sans can feel the plug being pushed to the side, one of the blasters lapping at where he's spread open around the toy, until he's wet and dripping. He pushes back against the tongue, whining with need. </em>
</p>
            </blockquote>





	Siblinglove

**Author's Note:**

> Title is a translation of Die Ärzte song Geschweisterliebe, for lack of any other suitable choice.
> 
> warnings: bestiality; improbable sex logistics (you do, in fact, need to use lube); mild come inflation; sex with animals, aka bestiality; mentions/minor pet play; oh, and bestiality.
> 
> The idea that skeletons have invisible inner organs from AgentFontySeven’s fic-Recognition at last: http://archiveofourown.org/works/5833960

Their basement is a dark damp place with exposed pipes running just underneath the ceiling and only a few bare light-bulbs to provide illumination.

 

Sans is crouched on the floor, bare except for the leash and collar around his neck. Red magic has pooled in his pelvis, casting red over white bones. A short black tail is nestled in the space between the pubis and the coccyx, curling up over his back, his magic anchoring the plug in place.

 

Papyrus lightly yanks Sans forward and Sans awkwardly shifts with along with the movement, dick bobbing, and he grunts a little as the movement jostles the plug inside of his asshole.

 

“I'VE GOT A SURPRISE FOR YOU, PET,” Papyrus coos, magic flaring as he summons his gaster blasters.

 

They form upwards out of swirling red magic, large and vaguely dog-like. They bound off to Sans, tongues lolling out as they greet their master's brother, cocks materializing even while they lick his face, affectionately.

 

Sans shivers as Papyrus' magic washes over him through the blasters. He wants this so much, loves being fucked like this as it permits his normally taciturn brother to readily display affection.

 

With a jolt, Sans can feel the plug being pushed to the side, one of the blasters lapping at where he's spread open around the toy, until he's wet and dripping. He pushes back against the tongue, whining with need.

 

At that, the blaster pulls back, paws pressing against Sans' back as it mounts him.

 

Sans gasps through the penetration, feeling his hole stretch to accommodate two insertions. The blaster slides forward smoothly until it's seated all the way inside before it starts pounding into him, fast and hard.

 

“THAT'S RIGHT. YOU LOVE THAT DOG COCK, DON'T YOU?” Papyrus says. “YOU'D DO ANYTHING TO GAIN MY APPROVAL.”

 

The cock continues to lengthen inside of Sans, and he keens as he's filled even more. He feels full, the blaster releasing precum to ease the way until his hole is sopping with it, dripping down his thighs and off his dick.

 

A nudge against his cheek has him looking up. Another blaster is standing in front of him, the tip of its dick sliding out of its sheath. Sans opens his mouth eagerly, crawling underneath to lick at the tip, the blaster behind scrabbling after him, its claws raking his sides. The blaster at his mouth thrusts forward, causing Sans to gag. But the blaster continues thrusting as Sans opens little by little, until its cock is all the way down his throat.

 

“GOOD BITCH. TAKING IT IN EVERY HOLE.” There's a touch against Sans' shoulder-blade, so soft he could almost swear he'd imagined it.

 

Sans can feel magic dripping onto his back, the blaster drooling as it fucks into him; can feel the cock in his ass start to swell around its base. With every thrust, he groans, the sounds vibrating up the cock in his throat, as the beginning of a knot rubs against his rim, the fit getting tighter and tighter until it catches and stays.

 

The blaster stills, growling as it starts to come. Sans can feel it slowly filling him up, his hole pulsing around the knot and insides milking the dick. The blaster in his mouth starts to thrust faster, the base swelling as his muffled noises stimulate it. With one hard shove, the blaster knots behind Sans' teeth, and Sans chokes a little as watery come floods his mouth, a little escaping from the side of his stretched jaw.

 

It doesn't seem to end, both blasters still ejaculating inside of Sans until he can feel the strain of his guts trying to handle everything being pumped into him. He wants, desperately, to be able to reach down and jack himself, to come, but he lacks the leverage, both arms needed to keep him up under both the combined weight of the blasters and the sensations running through him.

 

With the corner of his mind not given over to pleasure, Sans idly wonders what Papyrus is doing, if he's masturbating or if he's just staring at him in affected condescension, and wishes he could see beyond the blaster to where Papyrus is standing. Either scenario is hot.

 

After about twenty minutes, the blasters pull free. Strings of come are attached to their dicks and more drools out from both ends. The blasters back away and disappear, melting back into Papyrus' magic, rejoining their master. Two other blasters take their place.

 

Sans is still loose from the previous fucking, cock sliding into him without any trouble. The one in front of him quickly mounts his face, having learned from watching the previous coupling. Eyes half-lidded and unfocused, Sans is pliant beneath them, mewling softly as he's used again, as more magic is forced inside him.

 

The blaster at his back is impatient, thrusts harder and more brutal. It's odd to think of a magical weapon as having sentience, but it appears as though the time spent waiting had increased its arousal, knot growing more quickly. Its jaws clamp around the back of Sans' neck as it knots him, spilling more seed inside of Sans' already full guts.

 

Sans whimpers around the cock in his mouth, feeling a pleasantly uncomfortable strain as more come is forced into him. The blaster at his front is leisurely fucking his face, pulling out all the way before thrusting back inside. Tongue pressed against the underside of the cock, Sans could feel the knot growing, his mouth opening more and more each time the blaster buries itself inside of him.

 

With each thrust, spit and come leak from the corner of Sans' mouth, coating his lower jaw in with a fresh glaze of magic. Sans' normally invisible esophagus is coated in a faint sheen of red, bulging around the dick invading his throat. Another faint touch, this one against his throat, ghosts up and down along with the bulge in his gullet.

 

The blaster howls as Sans' throat clenches on its cock, forcing its knot into Sans' mouth and coming even as it still tries to ride his face, hips stuttering against Sans' cheekbones. More prepared this time, Sans gulps it down hurriedly, body welcoming his brother's magic.

 

The blaster behind him is finished first, pulling back with an obscene squelch, and Sans trembles as he feels come seeping from his gaping hole. He hangs, still attached to the blaster in his mouth, trying futilely to clench, to stop Papyrus' magic from leaving him.

 

The blaster in his mouth shifts, forcing Sans to move along with it, knotted and helpless. Stretched beyond its normal means for too long a period of time, his jaw aches even as he swallows around the dick in his mouth, drinking down its come.

 

By the time the other blaster is done with him, Sans is an utter wreck. It pulls away dematerializing and reforming with Papyrus' soul.

 

Papyrus looms over Sans, face hidden in shadows cast from the lights.

 

Sans looks up, tries his best to make eye-contact with Papyrus, swiping his tongue through the mess on his face. “More. I want your cock.”

 

“AND? WHAT DO YOU SAY?” Papyrus yanks the chain again, unbalancing Sans.

 

“Please, boss? Pretty fuckin' please?”

 

“WELL, IF YOU ASK SO _NICELY..._ ”

 

Papyrus walks out of Sans' line of sight, still holding the leash. Sans stays still, panting and eager for whatever Papyrus will give him.

 

He can hear Papyrus tittering over the mess he's made before a finger enters him, pushing the come that's escaped back into him. He stays as still as possible, trembling as he feels hands collecting all the fluids that had dribbled down his thighs then smearing it back into him, into his hole, before Papyrus' dick, thicker and longer than the others, pushes in, slowing the flow of come from his ass.

 

Sans is fucked out and sloppy around Papyrus' dick, come still oozing out of him with every thrust. Wet slapping noises echo through the basement, and Papyrus reaches around, jerking Sans' cock in time with his thrusts.

 

“SUCH A GOOD PET,” Papyrus hisses, “ALREADY WRECKED AND STILL BEGGING FOR MORE. PERFECT SLUT.”

 

Papyrus tugs at the plug still inside Sans, pushing and pulling at it and bumping it against Sans' insides and rubbing it against his own cock. Sans claws at the floor as his red and sore hole is tormented further, still gasping out pleas of _more, please, want more of you inside me. Fill. Me. Please_ as Papyrus inches his free hand down to Sans' stomach.

 

Gently, he massages the slightly bulging stomach, slowly starting to exert more pressure until he's pressing his hand hard into Sans' abdomen, come roiling and flowing faster down and out around the plug and Papyrus' dick. Sans come with a grunt, muscles clamping down. Papyrus fucks into the sudden tightness, once, twice, before he's spilling into Sans' heat, adding more of his magic to Sans' already flooded insides.

 

Sans feels warm and cared for, body strumming with Papyrus' magic. He closes his eyes, content to lay there and rest as Papyrus carries him upstairs to the shower.

 


End file.
